1. Field of the Art
This invention relates generally to electronic endoscopes which are in use in medical fields, and more particularly to an endoscopic terminal processor which contains within its casing an illumination light source along with a video signal processor for an electronic endoscope.
2. Prior Art
Electronic endoscopes which are currently in wide use for medical purposes are generally provided with an illumination window and an observation window side by side at the distal end of an insertion instrument to be inserted into a patient""s body cavity, permitting observation of an intracavitary site of interest under illuminated conditions. An electronic endoscope differs from an optical endoscope in that the endoscopic observation system employs an electronic image sensor means such as CCD camera or the like for an image pickup to be fitted in the observation window. Therefore, in the case of an electronic endoscope, a signal cable from the image sensor means is passed through an insertion instrument along with an illumination light guide from the illumination window, and extended into a universal cable which is led out from a manipulating head assembly of the endoscope. At a proximal end to be connected to an endoscopic terminal processor which contains an illumination light source along with a video signal processor, the universal cable is provided with a light connector and an electrical connector to couple the illumination light guide and the signal cable with the illumination light source and the video signal processor on the side of the terminal processor.
More particularly, the endoscopic terminal processor usually contains within its casing at least an illumination lamp unit, a video signal processing circuit board, a power supply unit, a transformer and an air pump for sending air or water into a body cavity through the endoscopic insertion instrument. The terminal processor is provided with light and electrical coupling portions on its front side to be coupled with the light and electrical connectors on the universal cable from the endoscope.
In this connection, of the various components which are mounted within the casing of the endoscopic terminal processor, the illumination lamp unit is usually composed of an illumination lamp, a condensing lens, a stop and a filter. The illumination lamp which is normally constituted by a high intensity lamp has a relatively short service life. Therefore, in order to facilitate replacement of the illumination lamp which takes place frequently, normally a couple of lamps are set on a lamp holder plate and, when one of the illumination lamp blows off, the other spare lamp is turned or slid into a light path leading to the light or optical coupling portion. For this reason, the illumination lamp unit is relatively large in size. Besides, it is usually the case that the illumination lamp unit, power supply unit, transformer and air pump are all fixedly mounted at the bottom of the terminal processor casing.
An endoscopic terminal processor of this sort is usually installed in an examination room of a hospital or clinic along with other diagnostic or therapeutic instruments or machines. Therefore, it is desirable for the endoscopic terminal processor to be as compact in size as possible. Since the illumination lamp unit is the largest one in size among the various components and circuit boards which are accommodated within the casing of the terminal processor, its mounting position is usually restricted to a considerable degree in relation with the position of the light coupling portion. Accordingly, various attempts have been made to make the terminal processor compact by appropriating locations of other components and circuit boards to this end. In this regard, it is important to take note of the fact that, as compared with other components and circuit boards, the video signal processing circuit board has a conspicuously broad surface area because of the necessity for mounting a large number of electronic parts including integrated circuits and so on, but is relatively small in thickness. Therefore, the compactness of the terminal processor as a whole depends on how the video processing circuit board is mounted within its casing.
In this regard, for example, it is conceivable to divide the video signal processor circuit board into a plural number of stackable circuit boards of smaller sizes which can be mounted compactly in a narrow space. However, the use of such stackable circuit boards could result in complication of wiring pattern and of connections between the individual boards. Since most of component parts of the endoscopic terminal processor are fixedly mounted on a bottom panel of the casing, it may occur to utilize an upper free space of the casing for mounting a video processing circuit board. In such a case, however, it may become necessary to form the video processor circuit board in a complicate shape other than a simple rectangular shape to evade other component parts which differ largely in height from each other, standing to different heights from the bottom panel of the casing. Therefore, this approach will invite a substantial increase in production cost of the circuit board due to complications of the production process.
If the component parts of the terminal processor are arranged in right and left groups which are located on the right and left sides of a center line of the terminal processor casing, a space of a certain width can be opened up centrally of the casing along the entire length thereof. In such a case, a rectangular video processor circuit board with a broad surfaces area can be compactly accommodated in that narrow space by mounting same in a vertical or upright position instead of in an ordinary horizontal position. In case a video signal processor circuit board is mounted vertically within an endoscopic terminal processor casing, it has to be fixedly supported on either top, side or bottom panel of the casing. However, if the video signal processor circuit board is fixed to only one wall of the casing, it can be destabilized when vibrating movement is transmitted thereto. In order to prevent this, in addition to one of side panels of the casing, the circuit board should be fixed at least to the bottom panel and/or the other side panel of the casing.
Besides the demands for compactness and downsizing, endoscopic terminal processors are required to have a lightweight structure. For this purpose, endoscopic terminal processor are usually reduced in thickness of side, top and bottom walls, and therefore are very susceptible to deformations when an impact is applied thereto, for example, by collisional contact with other object. When an impact is applied on one side of a terminal processor casing, for example, the applied force can be transmitted directly to a video processor circuit board in the casing to cause deformations, disconnections or other damages to the circuit board.
In view of the foregoing situations, it is an object of the present invention to provide an endoscopic terminal processor of the sort which accommodates within its casing an illumination light source along with a video signal processor for an electronic endoscope, supporting a video processing circuit board of the video processor within the casing vertically in a compact form and securely in a stabilized state against external forces which might otherwise cause deformation or damage to the circuit board or its support member.
In accordance with the present invention, the above-stated objective is achieved by the provision of an endoscopic terminal processor, which comprises: a casing accommodating therein an illumination light source along with a video signal processor for an electronic endoscope, and having optical and electrical coupling portions thereon, the illumination light source including an illumination lamp unit to be optically connected to an illumination light guide from the endoscope through the optical coupling portion for transmission of illumination light, and the video signal processor including a video signal processing circuit board to be connected with a signal cable from the endoscope through the electrical coupling portion; the video signal processing circuit board being supported in an upright position within the casing, and being fixedly connected at one end thereof to a side panel of the casing and loosely supported at the other free end on a damper member adapted to restrict flapping movements of the circuit board about the fixed end.
In a preferred form of the present invention, the damper member is fixed on a bottom surface of the casing, and provided with a pair of gripping plate portions adapted to hold a lower edge portion of the circuit board from opposite sides. Desirably, a noise shielding perforated structure is fitted on and around the circuit board. In some cases, the video signal processing circuit board is composed of a couple of circuit boards, i.e., a circuit board of the patient""s side and a circuit board of the secondary side. In such a case, one end of the circuit board of the patient""s side is fixed to an inner surface of an end panel of the casing, while one end of the circuit board of the secondary side is fixed to an inner surface of the opposite end panel of the casing. Each one of the other free ends of the two circuit boards is supported loosely on a damper member, and an isolation means is interposed between the two circuit boards to permit signal transmission there between in an electrically isolated state.
The above and other objects, features and advantages of the present invention will become apparent from the following particular description of preferred embodiments, taken in conjunction with the accompanying drawings.